There is prety nice documentation guide that comes with the bundle and a lot of real examples there too. Look at them carefully, give them a try!
If you have something unclear after that use forum search functionality and try to find the answer you are looking for!
And just after you did all this come back to this forum, describe your problem and your environment (jBPM version, DB, app server, OS) and ask your question!
Also there is detailed wiki page where you can start at http://www.jboss.com/wiki/Wiki.jsp?page=JbpmWiki
All said counts for your next two posts!
Sorry for not being that polite but if you have some preliminary knowledge about jBPM and ask concrete questions we here at the forum will try to help you as fast as we can.